Many user devices, such as smartphones, include haptic capabilities. For example, a conventional beeper may include an eccentric-rotating mass powered by a battery that can generate vibrational effects when activated. Other types of haptic devices may be incorporated as well, such as electrostatic friction haptic output devices. ESF devices generate high voltage static fields, e.g., 2 kilovolts (kV), on a surface, which can attract, for example, the skin on a user's finger towards the surface.